The present invention relates to a multi-phase PSK (phase shift key) demodulator.
Important parts of a PSK demodulator circuit normally include a carrier synchronizer (regenerator) and a multi-phase data demodulator means by detecting the input signal with the reproduced carrier. Numerous circuits concerning the carrier synchronizer have been disclosed before including popular ones such as Costas loop, Nth power loop and early-late gates loop. The Costas loop has potential phase detector imbalance problem, whereas the Nth power loop can have "ideal power" problems. And most of these circuits process input signal with analog mixer, phase shifter and voltage summer. In practice, their performance is easily suffered from the circuit impairments such as offset voltage, internal noise and delay accuracy.